The 2MIG isolated AGNs - I. General and multiwavelength properties of AGNs and host galaxies in the northern sky

Abstract

The host isolated galaxies with active galactic nuclei (AGNs) are unique for recognizing their internal multiwavelength properties and physical parameters of accretion on the supermassive black holes outside of the environment. For detaching these effects, we studied the galaxy sample obtained by cross-matching the 2MIG (2MASS isolated galaxy) catalogue with the Véron-Cetty catalogue of quasars and AGNs, which is limited to K_s ≤ 12.0 mag and V_r < 15 000 km s^-1. In this paper, we present a full description of 36 2MIG isolated AGNs in the northern sky (δ ≥ -15°). They were classified into several categories (pure and weak isolated AGNs, composites, and with faint companions) to reveal their multiwavelength properties including all the available archived data from literature and data bases. We found that most of the 2MIG northern isolated host galaxies with AGNs belongs to S0-Sc types (about 40 per cent are of Sb type), and a half of them are Sy2-type galaxies; the 2MIG isolated AGNs are mostly faint sources from radio to X-ray ranges; the positions of three galaxies (CGCG179-005, UGC10774, CGCG248-019) in BPT diagrams that were early classified as Seyfert galaxies reside on the valley of H II type of nuclear activity. For the first time, we revealed that the host isolated galaxies with AGNs of Sy1 type (without faint companions) appear to possess the bar morphological features. This suggests that a bar is crucial to the existence of broad-line region (BLR) in an isolated host galaxy providing transfer of gas and dust from galaxy's disc to AGN region. Therefore, the interaction with neighbouring galaxies is not necessary condition for BLR formation.